WASHINGTON -- In advance of House Speaker John Boehner's Florida fundraising event with Rep. Vern Buchanan (R-Fla.) on Saturday, the Democratic Congressional Campaign Committee has launched a new ad attacking Buchanan, the House's top Republican fundraiser, for his allegedly illegal campaign finance efforts.

The new ad, to be featured atop gas pumps in Buchanan's hometown of Sarasota, Fla., comes after The New York Timesadmonished Boehner for agreeing to appear alongside Buchanan at a weekend gathering of wealthy GOP donors.

Proceeds from Saturday night's event will go to benefit Boehner's leadership PAC, with supporters paying between $500 and $10,000 for a chance to have their photo taken with the House speaker.

Buchanan's scheduled presence has raised eyebrows because federal officials are currently looking into allegations that the congressman, who serves as vice chairman of finance for the National Republican Congressional Committee, reimbursed employees for contributing $90,000 in illegal straw donations to his campaign, as well as accusations that he failed to disclose relevant business positions at more than a dozen companies.

The DCCC in a statement on Saturday contrasted Boehner's slated appearance alongside Buchanan with his "zero tolerance" policy for lawmakers who have breached ethical standards.

"The chance of Speaker Boehner following his 'zero tolerance' pledge on ethics violations is now zero," said DCCC spokesman Jesse Ferguson in the Saturday statement. "Republicans have a campaign Finance Chairman who uses potentially illegal campaign finance tactics and is facing federal investigations but all Speaker Boehner wants is to fundraise off Congressman Buchanan's network."

The Office of Congressional Ethics ruled in October that there is "substantial reason to believe that Representative Buchanan violated House rules, standards of conduct and federal law," and the House Ethics Committee opened a fresh investigation into Buchanan's conduct.